Hygrothermal analysis for the electrochemical migration failure in multi-chip packages during a highly accelerated stress test

In this work, as one of the failure modes of electronics packages, electrochemical migration failure of a multi-chip package is addressed. Two types of multi-chip packages which consist of an encapsulated molding compound, two chips, a spacer, adhesives, and a substrate, are investigated. The hygroscopic properties of these materials are measured and the moisture concentrations of the spacers are investigated by a finite element analysis. It was concluded that adhesive under the top chip severely degrades the reliability of the package.